1. Field of the Invention
This invention relates to a vehicle transmission (speed change apparatus) which comprises a speed change ratio change mechanism (speed change mechanism) which can change a speed-change ratio in n shifts, an operating mechanism for operating the speed change mechanism to one of n shifts, an actuator mechanism for driving the operate mechanism, a handle mechanism to be handled in a shift-up direction or shift-down direction, and an ECU (Electric Control Unit) for controlling the actuator mechanism.
2. Related Art
A vehicle transmission which has a synchromesh-type speed change mechanism or a planetary gear-type speed change mechanism can include an up/down handle portion (for example, an up/down lever) that is handled or shifted in one of the two directions corresponding to an increase/decrease of the speed-change ratio to move the speed-change ratio up or down one shift by one shift or one shift at a time. A conventional vehicle transmission which has the synchromesh-type speed change mechanism and in which the up/down lever is provided is explained below with reference to FIGS. 4 and 5.
As shown in FIG. 4, a vehicle transmission 1 is provided with a speed change casing 2, a switch panel 8 which has an up/down lever 7 to be handled or shifted in one of the two directions corresponding to an increase/decrease of the speed-change ratio, and a ECU 9 which detects a shift of the up/down lever 7 and operates the actuator 6 so that the speed-change ratio is increased or decreased one shift at a time. Provided in the speed-change casing 2 is a gear train 3 for speed-change, a plurality of synchromesh mechanisms 4a to 4c to change (shift) combination of meshed gears of the gear train 3, an operating mechanism 5 which operates or moves the synchromesh mechanisms 4a to 4c to change the speed-change ratio of the gear train 3, and a hydraulic or electrical actuator 6 to drive the operate mechanism 5.
The operating mechanism 5 is comprised of a shift/select shaft 51 shifted in a shift (axial) direction and a select (rotate) direction by the actuator 6, and a predetermined number of shift forks (here, three shift forks 52a to 52c corresponding to five forward shifts and one backward shift) to operate the synchromesh mechanisms 4a to 4c based on a shift/select movement of the shift/select lever 51 by the actuator 6. The shift fork 52b corresponds to a first shift in which a transmitted torque is largest and the degree of reduced rotation is the smallest, and a second shift; the shift fork 52a corresponds to a third shift and a fourth shift; and the shift fork 52c corresponds to a fifth shift in which the transmitted torque is smallest and the degree of reduced rotation is largest, and a backward shift. The shift/select shaft 51 and the shift forks 52a to 52c are connected with each other by a gate member 53. The gate member 53 connects one of three shift forks 52a to 52c with the shift/select shaft 51 by the shift/select movement thereof.
The actuator 6 can be comprised of an electrical motor, hydraulic motor or oil/air cylinder, and a cooperating movement convert mechanism, and can move linearly and rotate the shift/select shift 51 or can move linearly and slide the shift/select shaft 51.
The up/down lever 7 is up-handled (shifted) to increase the speed-change ratio and is down-handled to decrease the speed-change ratio. In order to allow such operation of the up/down lever 7, as shown in FIG. 5, an up (speed increase)-groove 81 which extends in a speed increase direction, and a down (speed decrease)-groove 82 which extends in a speed decrease direction are formed on an operating panel 8. The up/down lever 7 can be also operated to a neutral position and a backward movement position and so a lateral groove 83 which extends from an intermediate position between the up-groove 81 and the down-groove 82 to the neutral position, and a backward movement groove 84 which extends from the lateral groove 83 in parallel with the up-groove 81 are also formed.
In the above vehicle transmission, when the up/down lever 7 is shifted into the up-groove 81 during starting of the vehicle for example, the ECU 9 detecting this shift selects the shift fork 52b for the 1st shift or the 2nd shift and sends to the actuator 6 a command to shift the gear train 3 to a side of an input shaft A. The actuator 6 rotates the shift/select shaft 51 to connect it with the shift fork 52b via the gate member 53, and then it moves the shift/select shaft 51 to the side of the input shaft A. Thus, the shift fork 52b is moved to the same side so that the synchromesh mechanism 4b is operated by a fork 54b provided at a tip end of the shift fork 52b to change the gear train 3 to the 2nd shift.
On the other hand, when the up/down lever 7 is shifted into the down-groove 82, the ECU 9 detected this shift selects the shift fork 52b and sends to the actuator 6 a command to shift the shift fork 52b to a side of an output shaft B. Thus, the synchromesh mechanism 4b and the gear train 3 are shifted to the 1st shift.
In the above vehicle transmission, while the vehicle is running in the 3rd shift, if the up/down lever 7 is shifted into the up-groove 81, the transmission is changed up to the 4th shift by operation of the shift/select shaft 51, the gate member 53 and the shift fork 52a. If the up/down lever 7 is shifted into the down-groove 82, the transmission is changed to the 2nd shift by operation of the shift/select shaft 51, the gate member 53 and the shift fork 52b. This speed increase or speed decrease one shift by one shift is carried out by every shift of the up/down lever 7 into the up-groove 81 or the down-groove 82, or by leaving the up/down lever 7 in the up-groove 81 or in the down-groove 82.
During vehicle driving, there are situations where a driver wishes to change the 5th shift to the 3rd shift or to the 2nd shift at a stroke when the vehicle is running on an ascending road for example, or to change the 3rd shift to the 5th shift when the vehicle is running on a descending road (such shift is called xe2x80x9cskip-shiftxe2x80x9d hereinafter). In the conventional vehicle transmission, the speed-change can be carried out only one shift by one shift, so that the driver should shift the up/down lever 7 into the up-groove 81 or the down groove 82 twice or thrice for the skip shift. Such shift however needs a long time for the speed-change operation, and delays the speed increase/decrease response of the vehicle, which does not satisfy the driver""s requirement.
The present invention is made in view of the above circumstances and intends to provide the vehicle transmission in which the vehicle speed can be changed by a one shift or a skip shift selectively based on the intention and shift operation of the driver. Here, xe2x80x9cone-shiftxe2x80x9d means the vehicle speed is changed from the x-th shift to the (x+1)th shift or to the (xxe2x88x921)th shift, in a vehicle transmission having the speed change mechanism to be changed in n shifts including m forward shifts and (n-m) backward shifts. Also, xe2x80x9cskip-shiftxe2x80x9d means the vehicle speed is changed from the x-th shift to the (x+2)th or more shifts or to the (xxe2x88x922)th or lesser shift (here, the relationship 3xe2x89xa6xc3x97xe2x89xa6(mxe2x88x922) is satisfied).
In order to achieve the above object, the vehicle transmission according to the present invention is comprised of a speed change mechanism capable of changing the speed-change ratio in n shifts; an operating mechanism having n operating routes to changing the speed-change ratio of the speed change mechanism in one of n shifts via any of n operating routes; an actuator mechanism for driving the operate mechanism; a one-shift handle portion adapted to be handled to one-shift the speed change mechanism; a skip-shift handle portion handled to skip-shift the speed change mechanism; and an ECU for controlling the actuator mechanism based on the handling of the one-shift handle portion or the skip-shift handle portion. Based on control by the ECU, the actuator mechanism drives the operate mechanism via any of n operating routes to change the speed change mechanism one shift by one shift or more than two shift in one stroke, selectively.
According to the above vehicle transmission, when the driver wishes to change the vehicle speed by the skip shift, he or she shifts a skip-shift handle portion prior to or simultaneous with shift of the one-shift handle portion. Based on this shift of the skip-shift handle portion, the ECU having detected the shifted position of the up/down handle portion drives or controls the actuator so that the vehicle speed is skip shifted from the x-th shift to the (x+2)th shift or to the (xxe2x88x922)th shift. By this way, the speed increase/decrease response of the vehicle transmission on the sloped road can be improved to satisfy the driver""s requirement.
The vehicle transmission of the present invention can include the following embodying modes or variation.
The speed change mechanism can be a planetary gear type, or the synchromesh type. When the present invention is applied to the vehicle transmission which has the planetary gear type speed change mechanism, the actuator mechanism drives a brake mechanism or a clutch mechanism which controls a meshing of the planetary gear. The vehicle transmission which has the synchromesh mechanism type speed change mechanism and to which the present invention is applied will be explained in detail in the preferred embodiment.
The number of shifts of the vehicle speed change mechanism is n which comprises m forward shifts and (n-m) backward shifts. At least, the number m for the forward shifts can be selected within the integer equal to or larger than 3, and is preferably 4, 5 or 6.
The speed change mechanism is comprised of n/2 (when the number of shifts n is an even number), or (n+1)/2 (when the numbers of shifts n is odd number) change portions, and each of the speed change portions corresponds to adjust two of the n shifts.
The operating mechanism includes n/2 or (n+1)/2 shiftable operating portions, and one direction movement and another direction movement of each of the operating portions correspond to the adjacent two shifts, respectively. The operating mechanism to operate the vehicle speed change mechanism by one-shift and the operate mechanism to operate the vehicle speed change mechanism by skip-shift can be separately provided, or the same operating mechanism can be commonly used for both of them.
The actuator mechanism includes n/2 or (n+1)/2 actuators, and each of the actuator drives each of the operate portions, respectively. The actuator mechanism for driving the operate mechanism for the one-shift, and the actuator mechanism for driving the operate mechanism for the skip-shift can be separately provided, or the same actuator mechanism can be commonly used for both of them.
The commonly used operate mechanism and the commonly used actuator mechanism can contribute to make the entire vehicle transmission compact. As the actuator mechanism, a hydraulic oil or air cylinder, an oil motor or an electrical motor can be used.
The one-shift handle portion can be a lever or a switch, and the skip-shift handle portion can be a button or a switch. The skip-shift handle portion is preferably disposed on a knob (for example, on an inner side thereof) when the one-shift handle portion is comprised of a lever, or on a predetermined position on a steering wheel, to be handled by the driver seated on the driving seat by his or her intention, but is rarely touched for the speed-change. Here, the inner side of the knob means a side facing the driver, i.e. the side of the thumb of the left hand. Thus, an erroneous handling of the skip-shift handle portion be can avoided.
The skip-shift handle portion is preferably handled prior to or simultaneous with the handling of the one-shift handle portion (if it is handled after the handling of the skip-shift handle portion, the speed increase/decrease response which can satisfy the driver""s requirement will not be realized).